Hydropneumatic recuperator with adjustable power



Nov. 6, 195] J. E. PRACHE 2,574,060

HYDROPNEUMATIC RECUPERATOR WITH ADJUSTABLE POWER Filed April 17, 1950 2 Sl-IEETS'--ShEET 1 INVENTOR mmmmyw ATTORNEYS Nov. 6, 1951 J. E. PRACHE 2,574,060

HYDROPNEUMATIC RECUPERATOR WITH ADJUSTABLE POWER INVENTOR' W W #Zlfibw ATTORNEY6 Patented Nov. 6, 1951 HYDROPNEUMATIC RECUPERATOR WITH ADJUSTABLE POWER Jacques Emilien Prache, Fontenay-sous-Bois,

France, assignor to Societe des Forges et Ateliers du Creusot, Paris, France, a joint-stock company Application April 17, 1950, Serial No. 156,248 In France April 20, 1949 4 Claims.

This invention relates to hydro-pneumatic trecuperators especially adapted for use with artillery intended to fire at relatively large angles of elevation, and is particularly directed to improvements in the recuperators disclosed in Figs. 1 and 2 of copending application Serial No. 743,998, filed April 25, 1947.

The principal object of the present invention is the same as that of the above mentioned pending application, namely, to provide novel means for automatically regulating, as a function of the angle of elevation of the gun, the power possessed by the recuperators of braking and of returning into battery position without modifying their initial latent energy. This result is obtained by varying the initial volume of the air subjected to compression during recoil (which may be designated as the useful air) in accordance with changes in the laying angle, but without changing its pressure.

As the result of a thorough study of recuperators of the character illustrated in Figs. 1 and 2 of application Serial No. 743,998, wherein a liquid medium is displaced during recoil of the gun and serves to compress the useful air in a compartment of variable volume constituting the forward end of the air reservoir, it has been found that, as the angle of fire approaches the vertical, there is an increasing tendency for the liquid of the recuperator to leak into the rear compartment of the air reservoir wherein is confined the mass of air which is protected from the effect of the recoil.

It is therefore a particular object of the present invention to overcome this disadvantage of the prior structures either by interposing a floating piston between the separating piston which divides the air reservoir into the two compartments and the orifice through which the liquid flows into said reservoir to compress the air, thereby ensuring separation of the two fluids, or by so changing the positions of the elements that the compartment containing the air which is to be protected from the efiect of the recoil is located in front of, rather than to the rear of, the separating piston, and that the orifice between the recuperator cylinder containing the liquid and the compartment containing the mass of air which is to be compressed is located at the rear end of said compartment. In the latter embodiment, the separating piston will, of course, be controlled in such a manner that its displacements are opposite to those received by the pistons in the corresponding embodiments of application Serial No. 743,998.

Referring now to the drawings, wherein like reference characters indicate like parts throughout the several views;

Fig. l is a diagrammatic sectional elevation of a hydro-pneumatic recuperator constituting one embodiment of the invention;

Fig. 2 is a similar view of a modification of the arrangement shown in Fig. 1; and

Fig. 3 is a similar view of another form of recuperator wherein the improvement of the present invention is applied similarly to Fig. 2.

The devices shown in Figs. 1 and 2 are of basically the same construction as that of Fig. 1 of application Serial No. 743,998, while Fig. 3 herein is comparable to Fig. 2 of the earlier case.

In the embodiment of the invention illustrated in Fig. 1, the recuperator comprises a cylinder I connected to and movable with the cradle 2 which oscillates about horizontal trunnions 3 on the gun carriage 4 during laying of the gun in elevation. Movable in the cylinder 1 is a piston 5 which is connected to a member 6 forming part of the recoiling mass of the gun, and which, when the recoil takes place, forces liquid from the cylinder 1 into an air reservior 1 formed integrally with said cylinder and with which the latter communicates freely through a channel 8 and an orifice 8a. In the structure shown, the orifice 8a leads into the front portion of the reservoir 1, i. e. the end thereof closest to the muzzle of the gun. The interior of the reservoir 1 is divided into two compartments a and b by a separating piston 9 having a rod 9a which eX-' tends in an airtight manner through the rear end of the reservoir and carries at its outer end a roller II] which, when the gun is elevated, is constrained to follow an arcuate path defined by a guide or directing groove ll integral with or fixed to the gun carriage 4 and having a suitable profile for the purpose hereinafter described.

The separating piston 9 is provided with a passageway or conduit 9b extending there through in a direction parallel to the piston rod 9;. and wherein is mounted a valve I3 which is maintained in open or unseated position when the gun is at rest by a relatively weak spring M, thus permitting air to pass between the two compartments a and b. As soon as recoil begins, the valve I 3 closes and interrupts communication between the two compartments throughout the recoil movement and until the end of the return movement to battery position. The piston 9 may, if desired, be provided with a compensating piston rod 15 of the same diameter as rod 99. and extending in the opposite direction to the latter so as to equalize the areas of the opposite faces of the piston 9 which are subjected to the pressure of the air in the compartments u and b.

According to the present invention, the reservoir I also houses a movable fluid-tight partition or floating piston 18, interposed between the one out recoil and counter-recoil and reopens only when the gun has come to rest, at which time the pressures in compartments a and b are equal and the spring I4 is eifective to open'the valve and reestablish communication between the two compartments. 7

It will be apparent from the foregoing description that the floating piston 19. constitutes a bar- I rier against leakage of liquid from the chamber 1c intothe'air compartments a and b which is 7 effective at all times regardless of the angle of elements, suitable packing being provided, for

forming a fluid-tight seal therebetween; The piston 1a also carries similar packing for sealing its outer periphery against the surrounding Wall of the reservior 1. r I

When, under the action of the gun elevating mechanism, the cradle 2 is subjectedto a positive angular displacement about the trunnion's 3, the roller l0, moving in the {groove H, causes the piston 9 to slide toward the front of the reservoir 1. During this displacement of the piston, the chambers a and I) remain in communication with one another, the spring 14 being so callbrated as to maintain the valve l3 in open position even when the angular velocity of the gun laying movement is ata maximum. There is then'an exchange of air between chambers 11 and bwithout any variation in pressure, the total volume remaining constant. The chamber a,

which is intended to confine the volume of useful air which is subject to compression during recoil, thus changes in volume as a function of the angle of elevation of the gun, according to the law. imposed by the profile of the groove ll.

When the gun is fired, after having been laid at any desired angle of elevation, the recoiling member 8-draws the recuperator piston 5 rearwardly in the cylinder I and thereby forces liquid from said cylinder through the channel 8 and orifice as. into that portion of the reservoir 1 which lies in front of the floating piston Ta, forming the chamber 10. It willbe understood that the chamber 10, the channel 8 and the portion of cylinder l lying to the rear of piston 5 are always completely filled with liquid, and that the portion of cylinder l in front of the piston 5 may be vented to the atmosphere through an orifice la. As the recoil continues, the additional liquid which is forced into the chamber 10 pushes the floating piston 1a rearwardly so as to compress the air confined between it and the piston '9, the valve I33 closing as soon as the floating piston 1a starts its rearward movement. Compression of the air in the compartment a durin recoil thus stores up energy which is effective during counter-recoil to return the gun to battery, the amount of power stored depending solely upon the volume of the chamber a, at the angle of elevation of the gun at the time of firing.

During the return to battery, the floating piston 19. is moved forwardly and returned to its initial position abutting the stops 1b by expansion of the air in compartment a, and the excess liquid in chamber 10 is forced back through the orifice 8a and channel 8 into cylinder I as the piston 5 also moves forwardly to its original position. Since the air pressure in compartment it remains greater than that existing in compartment 1) until the return to battery position is completed, the valve It remains 'closed'throughelevation of the gun.

In the structure shown in Fig. 2,'the'fioating piston Te and channel 8 of Fig. 1 are omitted the piston rod 9a and compensating piston rod [5 are lengthened .and shortened, respectively, so that the piston 9 is adjacent the front, rather than the rear, end of reservoir 1 when the gun is horizontal; the relative disposition of the compart- 7 ments a and b of the reservoir is reversed in comparison with the embodiment of Fig. 1-; and the orifice 8a through which the liquid 'fiows from the cylinder I into the reservoir 1 is located at the rear end of the compartment a and provides direct communication between said compartment and said cylinder. The valve [3 in Fig. 2 is also inverted relativel to the position shown in Fig.

1. Since the separating piston 9 in the embodiment of Fig. 2 must be displaced rea'rwardly as the elevation angle of the gun increases, the guide or directing groove H in which the'rolle'r l8 operates is also differently shaped and positionedrelatively to the trunnion's 3' than in the embodiment of Fig. 1.

It will be readily apparent that, With the arran'gement shown in Fig. 2,leakage-of liquid into compartment 2) is eiiectively prevented because,

at all angles of elevation of the gun above the horizontal, gravityitself opposes any tendency of,

the liquid to flow forwardly between the piston 9 andthe surrounding wall of the reservoir I. It' will be understood, of course, that the fit of the piston 9 in the reservoir 1 sufficiently tight to prevent such leakage when the gun is horizontal.

The embodiment of the invention illustrated in 7 Fig. 3 is basically the same as that of Fig.2 except that communication between the compartments a and b is effected through a by-pass conduit I! in the wall of the reservoir 1., instead of through a valve-controlled passageway in the piston 9, the latter being solid in the device of Fig. 3. The fiow of air between compartments a and 12 through the conduit, is controlled by a'cock I8 which is positivelyactuatedin"any suit--.

able manner, as by a dog l8 having arms of unequal lengths, said dog being-fixedto and carried by the member 8 of the recoiling mass and acting on a crank arm 19 connected to the cock.

When the gun is, in battery, the cock -18 is in V the open position illustrated, in'Figr3 butas'soon as the recoil begins, itis closed by, the forward or shorter leg of the "dog l8 which, after the closing, releases-the crank I9 and leaves it in-a position such that, upon counter-recoil and return of the gun tobattery, the rear or longer leg of the dog l8v engages the crank and reopens tive positions of the compartments. wand ibi---are reversed, and the orifice 8a through which the cylinder I and air reservoir 7 communicate is located to the rear, instead of in front, of the piston 9. Leakage of liquid from compartment a into compartment 1) is prevented in the same mamier as that previously described in connection with the embodiment of Fig. 2 herein.

The devices of the present invention have the same basic advantages and utility as those of application Serial No. 743,998, but are additionally beneficial in that they embody means for effectively preventing the liquid of the recuperator cylinder from gaining access to that compartment of the air reservoir wherein is contained the mass of air which is protected from the effect of the recoil.

- What is claimed is:

1. In a hydro-pneumatic recuperator for a gun of the variable power type wherein the accumulation of recuperating energy results from movement of the recoiling mass of the gun and the amount of energy accumulated varies with the angle of elevation of the gun prior to recoil, a cylinder movable to various angular positions relative to the horizontal in accordance with the angle of elevation of the gun, a piston in said cylinder located adjacent the forward end thereof when the gun is at rest, the portion of said cylinder to the rear of said piston being filled with a liquid, a piston rod connecting said piston to the recoiling mass of the gun, an air reservoir fixed to and movable with said cylinder to various angular positions relative to the horizontal, a piston in said air reservoir separating the latter into two compartments, one of said compartments containing air adapted to be compressed durin recoil of the gun and the other compartment containing air which is protected from the recoil efiect, means for varying the position of said separating piston in said reservoir according to the angle of elevation of the gun prior to recoil, means providing free communication for the flow of liquid from said cylinder into said first named compartment of said reservoir, and means independent of said separating piston effective at all angles of elevation of the gun for preventing the leakage of liquid into said second named compartment.

2. In a hydro-pneumatic recuperator for a gun of the variable power type wherein the accumulation of recuperating energy results from movement of the recoiling mass of the gun and the amount of energy accumulated varies with the angle of elevation of the gun prior to recoil, a cylinder movable to various angular positions relative to the horizontal in accordance with the angle of elevation of the gun, a piston in said cylinder located adjacent the forward end thereof when the gun is at rest, the portion of said cylinder to the rear of said piston being filled with a liquid, a piston rod connecting said piston to the recoiling mass of the gun, an air reservoir fixed to and movable with said cylinder to various angular positions relative to the horizontal, a piston in said air reservoir separating the latter into two compartments, the compartment forward of said piston containing air adapted to be compressed during recoil of the gun and the compartment to the rear of said piston containing air which is protected from the recoil effect, means for varying the position of said separating piston in said reservoir according to the angle of elevation of the gun prior to recoil, said separating piston being located adjacent the rear end of said reservoir when the gun is horizontal and being movable forwardly as the angle of elevation increases, means including an orifice in the wall of said reservoir adjacent the forward end thereof providing free communication for the flow of liquid from said cylinder into said reservoir, and means effective at all angles of elevation of the gun for preventing the leakage of liquid into the air compartment to the rear of said separating piston including a floating piston in said reservoir interposed between said ori fice and said separating piston.

3. A recuperator as claimed in claim 2 including a conduit filled with liquid connecting the rear end of said cylinder with said orifice, the portion of said reservoir in front of said floating piston also being filled with said liquid, and means for limiting the forward movement of said floating piston to a position immediately to the rear of said orifice.

4. In a hydro-pneumatic recuperator for a gun of the variable power type wherein the accumulation of recuperating energy results from movement of the recoiling mass of the gun and the amount of energy accumulated varies with the angle of elevation of the gun prior to recoil, a cylinder movable to various angular positions relative to the horizontal in accordance with the angle of elevation of the gun, a piston in said cylinder located adjacent the forward end thereof when the gun is at rest, the portion of said cylinder to the rear of said piston being filled with a liquid, a piston rod connecting said piston to the recoiling mass of the gun, an air reservoir fixed to and movable with.said cylinder to various angular positions relative to the horizontal, a piston in said air reservoir separating the latter into two compartments, the compartment to the rear of said separating piston communicating with the liquid filled portion of said cylinder and containing air adapted to be compressed by said liquid during recoil of the gun and the compartment forward of said piston containing air which is protected from the recoil effect, means for varying the position of said separating piston in said reservoir according to the angle of elevation of the gun prior to recoil, said separating piston bein located adjacent the forward end of said reservoir when the gun is horizontal and being movable rearwardly as the angle of elevation increases, and an orifice in the wall of said reservoir adjacent the rear end thereof providing free communication for the flow of liquid from said cylinder into the compartment of said reservoir to the rear of said separating piston, the location of'said orifice assisting in preventing the leakage of liquid into the air compartment forward of said separating piston at all angles of elevation of the gun.

JACQUES EMlLIEN PRACHE.

No references cited. 

